<!DOCTYPE html>
<html>
<body>

<p>Click the first button to alert "Hello" after waiting 5 seconds.</p>
<p>Click the second button to prevent the first function to execute. (You must click it before the 5 seconds are up.)</p>

<button onclick="myFunction()">Try it</button>
<button onclick="myStopFunction()">Stop the alert</button>

<script>
var myVar;

function tt() {
	window.alert("Hello");
}

function myFunction() {
  myVar = setTimeout(tt, 5000);
}

function myStopFunction() {
  clearTimeout(myVar);
  
}
</script>

</body>
</html>
